Apparatus for driving an automatic door



APril 1969 KUNIMORI MARUYAMA 3,438,274

APPARATUS FOR DRIVING AN AUTOMATIC DOOR Filed Sept. 27, 1967 United States Patent 3,438,274 APPARATUS FOR DRIgNG AN AUTOMATIC DO R Kunimori Maruyama, Tsurumi-ku, Yokohama, Japan, assignor to Takeshi Yamamoto, Tokyo, Japan Filed Sept. 27, 1967, Ser. No. 670,910 Claims priority, application Japan, Sept. 29, 1966, 41/ 63,739 Int. Cl. F16h 19/02 U.S. Cl. 74-33 1 Claim ABSTRACT OF THE DISCLOSURE An apparatus for driving or operating an automatic door, comprising a pushing rod operatively connected to the door, and a pair of pulleys made of resin and arranged to pinch therebetween the pushing rod, one of which is driven by a driving motor through a gear integrally fixed to said one pulley, thereby admitting the frictional slipping between said pulleys and said pushing rod for eliminating any harm to a person and any overloading of said motor when a person is caught by the closing door.

BACKGROUND OF THE INVENTION This invention relates to an apparatus for driving an automatic door.

Heretofore, the apparatus of this kind has such a construction that two sprockets are mounted on a driving shaft, and on a frame, respectively, these sprockets being wound by a chain belt to which a part of the door is fixed. In such conventional apparatus, sufficient driving is difficult to be effected since the chain belt is apt to be loosened; the chain belt causes noisy sound in operation; and the seizure of motor is apt to be caused by the overloading of the same and a human body is strongly pinched between the door and the door frame since the sprockets are not rotated when the human body is caught by the closing door.

SUMMARY OF THE INVENTION This invention aims to eliminate the above-mentioned faults and to provide an apparatus of this sort having a door driving rod and two grooved pulleys driven by a motor and arranged to pinch the rod therebetween so that the pulleys can be idled when a human body is caught by the door, for preventing any accident. Moreover, the apparatus of this invention functions without generating any noisy sound.

The subject matter of this invention accordingly resides in an apparatus for driving an automatic door, comprising a grooved pulley made of resin and fixed to a driving gear at its one side, said driving gear being fixed to a driving shaft, another grooved pulley made of resin and fixed to a follower gear at its one side, said follower gear being in meshed relation with said driving gear, and a door driving rod pinched by said grooved pulleys for actuation.

BRIEF EXPLANATION OF THE DRAWINGS The accompanying drawings show an embodiment of an apparatus for driving an automatic door of this invention, wherein FIGURE 1 is its side view, and FIGURE 2 is its front view.

DESCRIPTION OF THE PREFERRED EMBODIMENT Now, the apparatus of this invention will be specifically explained with an embodiment illustrated in the drawings. At one end of a driving shaft 1 driven by a motor (not shown), a driving gear 2 is fixed in a meshed relation with a follower gear 3 mounted on a follower shaft 4. On a side of said gears 2 and 3, two rubber pulleys 7 and 8 having arcuate cross-section grooves and 6, respec- "ice tively, are fixed so as to pinch a door driving rod 9 of a circular cross-section at their grooves 5 and 6 for allowing leftward and rightward replacements of the rod 9 by the rotation of the grooved pulleys 7 and. 8. In FIGURE 1, a reference numeral 10 shows a bearing disc for rotatably supporting one end of the driving shaft 1 and that of the follower shaft 4.

By virtue of the above-mentioned construction, the apparatus functions as follows: When a switching means such as a step-plate disposed in front of the door is actuated by a coming person, the driving gear 2 is rotated in the direction shown by an arrow in FIGURE 2 through the driving shaft 1 by the driving force of the motor, and accordingly the follower gear 3 is rotated in the direction as shown by an arrow in FIGURE 2. In accordance with the rotation of both gears, the grooved pulleys fixed to the one side of the gears 7 and 8 are also rotated in the same directions. Accordingly, the door driving rod 9 pinched between the grooves 5 and 6 is moved leftwards in FIGURE 2 for opening the door.

When the weight is removed from the step-plate, the gears 2 and 3 are rotated in the reverse directions by the reverse rotation of the motor for moving the door driving rod 9 rightwards to close the door.

Although it has been explained in the foregoing explanation that the grooved pulleys 7 and 8 are made of rubber, the invention is not limited to the use of such rubber only, but any appropriate synthetic resins may be used for this purpose.

For this reason, the material is herein mentioned merely as resin. Also, the cross-sectional shape of the grooves 5 and 6 of the pulleys 7 and 8 is not limited to the arcuate shape as shown, but may be of rectangular, trapezoidal or any desired shape as occasion demands. In accordance with the shape of the pulleys, the shape of the rod 9 of course should be varied.

Since this invention has the above-mentioned construction and function, the following technical merits can be attained: Even if the door is closed while a person remains within the swinging or sliding range of the door, the person would not be harmed since the movement of the door driving rod 9, which is merely pinched by the pulleys 7 and 8, will be stopped and the grooved pulleys 7 and 8 are slipped and idled without applying any excessive pressure to the person. Since the grooved pulleys 7 and 8 are thus idled, the motor would not be applied by excessive load and would not be seized. Furthermore, there is no fear to generate any noisy sound from the apparatus, since the actuation is effected by the pulleys 7 and 8 made of resin.

I claim:

1. An apparatus for driving an automatic door, comprising a grooved pulley made of resin and fixed to a driving gear at its one side, said driving gear being fixed to a driving shaft, another grooved pulley made of resin and fixed to a follower gear at its one side, said follower gear being in meshed relation with said driving gear, and a door driving rod pinched by said grooved pulleys for actuation.

References Cited UNITED STATES PATENTS 1,218,021 3/1917 Walther 74-422 2,617,139 10/1935 Wood 74--29 2,052,911 9/ 1936 Weathers 74-29 2,590,484 3/1952 Youhouse 7429 FRED C. MATTERN, 111., Primary Examiner. W. S. RATLIFF, 111., Assistant Examiner.

US. Cl. X.R. 7429, 422 

